Multi-disciplinary study of a new 3D cobalt (II) complex: from crystal engineering to antimicrobial drug potential

This study reports the preparation, spectroscopic characterization, and biological evaluation of a novel three-dimensional coordination complex, C10H24N6[Co(SCN)4]. The compound crystallizes in the P21/n space group, featuring a structure where terminally bound thiocyanate-N ligands bridge cobalt (II) layers to form a marginally distorted MN4 tetrahedral geometry around the metal center. Functional groups and vibrational modes were analyzed via FT-IR and UV-Vis spectroscopy, revealing a semiconductor nature with an energy gap of 4.1 eV and potential applications as a light-emitting device. Hirshfeld surface (HS) analysis and Density Functional Theory (DFT) calculations were employed to examine intermolecular interactions and electronic structures, confirming that the crystal’s stability is maintained by a network of weak electrostatic hydrogen bonds. Biologically, the complex demonstrated significant antimicrobial activity, acting as an inhibitory agent against pathogens such as Salmonella typhimurium and Escherichia coli. Molecular docking studies further validated its medicinal potential, showing binding affinities (−4.1 to −5.0 kcal/mol) comparable to the standard antibiotic ciprofloxacin. These findings highlight the compound’s promise in the fields of material photonics and medicinal chemistry. Magnetic studies confirm high-spin tetrahedral Co(II) behavior with orbital contributions, zero-field splitting, low-temperature spin-canted ordering, and frequency-dependent slow magnetic relaxation.